The present application claims priority to Japanese Application(s) No(s). P2000-368663 filed Dec. 4, 2000, and P2000-368664 filed Dec. 4, 2000, which application(s) is/are incorporated herein by reference to the extent permitted by law.
The present invention relates to a display device including an organic electroluminescence device, an electronic apparatus including the display device, and a method of producing the display device.
In recent years, attention has been paid to a display device including an organic electroluminescence device (hereinafter referred to as xe2x80x9corganic EL devicexe2x80x9d) as a light-emitting device.
Conventionally, in such a display device, a transparent electrode as anode is provided in a stripe form on a transparent glass substrate. On the stripe form transparent electrode, an organic layer is provided in an orthogonal direction. The organic layer is constituted of a positive hole transport layer and a light-emitting layer. A cathode is provided on the organic layer. With such a structure, the organic EL devices are provided at positions where the transparent electrode and the cathode intersect, and a light-emitting area is formed by arraying the organic EL devices in a matrix form. At a peripheral area of the glass substrate, an electrode portion for connecting the light-emitting area to a driving circuit is provided.
When a positive voltage is applied to the transparent electrode as anode and a negative voltage is applied to the cathode, positive holes injected from the transparent electrode pass through the positive hole transport layer to reach the light-emitting layer. On the other hand, electrons injected from the cathode reach the light-emitting layer. Thus, in the light-emitting layer, recoupling of the electrons and positive holes occurs, whereby light with a predetermined wavelength is generated, and the light is emitted through the transparent glass substrate to the exterior.
In such kind of display device, a flexible wiring board for connection to the exterior and a driver IC (integrated circuit) for driving are electrically connected to the electrodes on the glass substrate through an ACF (anisotropic conductive film) by heating the ACF.
FIG. 1 shows a connection example of an organic EL device 1000 with a driver IC 1001 and a flexible wiring board 1002. An example of electrical connection of a glass substrate 1003 of the organic EL device 1000 and the driver IC 1001 with the flexible wiring board 1002 is shown in FIG. 2. A transparent electrode 1004 of ITO film (indium tin oxide film) is provided on the glass substrate 1003. The driver IC 1001 is electrically connected to the transparent electrode 1004 by use of an ACF 1005. Similarly, the flexible wiring board 1002 is also electrically connected to the transparent electrode 1004 by an ACF 1006.
However, when the electrode portion on the glass substrate and the flexible wiring board or the driver IC are electrically connected by use of the ACF and by heating the ACF, there are following problems.
A monomer constituting the organic EL device can thermally resist only to about 80xc2x0 C., so that the organic EL device is weak to heat. Therefore, where the electrode portion on the glass substrate and the flexible wiring board or the driver IC are electrically connected by applying heat, such electrical connection by applying heat cannot be performed unless the electrode portion on the glass substrate is located much spaced from the organic EL device on the glass substrate.
It is an object of the present invention to provide a display device, an electronic apparatus and a method of producing a display device by which a conductive connection portion on a flexible wiring board can securely be electrically connected to a conductive metallic film on a substrate including an organic electroluminescence device, even at a position close to the organic electroluminescence device.
To achieve the above object, according to a first aspect of the present invention, there is provided a display device including:
a first substrate having an organic electroluminescence device,
a conductive metallic film provided on the first substrate, at such a position as not to overlap with the organic electroluminescence device,
a second substrate laminated on the first substrate, the second substrate including a plurality of holes, and conductive connection portions at peripheral portions forming the holes, and
solder portions packed in the holes in the second substrate and melted by laser light so as thereby to electrically connect the conductive metallic film on the first substrate and the conductive connecting portions of the second substrate.
With this configuration, the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side are electrically connected securely to each other by the solder portions.
In addition, the solder portions are located in the holes in the flexible wiring board and are melted by laser light, so that the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side can be electrically connected by only local application of heat. Therefore, thermal damage is not exerted on the organic electroluminescence device, so that the connection portions can be provided even at places close to the organic electroluminescence device.
In accordance with a second aspect of the present invention, the second substrate in the first aspect is a flexible wiring board.
In accordance with a third aspect of the present invention, there is provided an electronic apparatus having a display device including:
an organic electroluminescence device provided on a first substrate,
a conductive metallic film provided on the first substrate, at such a position as not to overlap with the organic electroluminescence device,
a second substrate laminated on the first substrate, the second substrate including a plurality of holes, and conductive connection portions at peripheral portions forming the holes, and
solder portions packed in the holes in the second substrate and melted by laser light so as thereby to electrically connect the conductive metallic film on the first substrate and the conductive connection portions of the second substrate.
With this configuration, according to a third aspect of the invention, the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side are electrically connected securely to each other by the solder portions.
In addition, the solder portions are located in the holes in the flexible wiring board and are melted by laser light, so that the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side can be electrically connected by only local application of heat. Therefore, thermal damage is not exerted on the organic electroluminescence device, so that the connection portions can be provided even at places close to the organic electroluminescence device.
In accordance with a fourth aspect of the present invention, there is provided a method of producing a display device including the steps of:
forming a conductive metallic film on a substrate having an organic electroluminescence device at such a position as not to overlap with the organic electroluminescence device,
adhering a flexible substrate provided with a plurality of holes around which conductive connection portions are provided to the substrate so that the metallic film corresponds to the holes in the flexible substrate,
throwing solder balls into the holes in the flexible substrate, and
melting the solder balls by laser light so as thereby to electrically connect the conductive connection portions of the flexible substrate and the metallic film of the substrate.
With this configuration, according to the fourth aspect of the invention, the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side can be electrically connected securely to each other by the solder balls.
In addition, the solder balls are located in the holes of the flexible wiring board and are melted by use of laser light, so that the conductive connection portions and the conductive metallic film on the substrate side can be electrically connected by only local application of heat. Therefore, thermal damage is not exerted on the electroluminescence device, and the connection portions can be provided even at places close to the electroluminescence device.
In accordance with a fifth aspect of the present invention, there is provided a method of producing a display device including the steps of:
forming a conductive metallic film on a first substrate having an organic electroluminescence device at such a position as not to overlap with the organic electroluminescence device,
packing a solder in a plurality of holes around which conductive connection portions are provided of a second substrate,
adhering the first substrate and the second substrate to each other so that the metallic film of the first substrate corresponds to the holes in the second substrate, and
melting the solder in the holes in the second substrate by laser light so as thereby to electrically connect the metallic film of the first substrate and the conductive connection portions of the second substrate.
With this configuration, according to the fifth aspect of the invention, the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side can be electrically connected securely by use of the solder.
In addition, the solder is located in the holes in the flexible wiring board and is melted by use of laser light, so that the conductive connection portions of the flexible wiring board and the conductive metallic film on the substrate side can be electrically connected by only local application of heat. Therefore, thermal damage is not exerted on the electroluminescence device, so that the connection portions can be provided even at places close to the electroluminescence device.
The above and other objects, features and advantages of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings which show by way of example some preferred embodiments of the invention.